I’m also looking at doing this. But I do have a question on DB sizes.
It looks like you generate a low-res, low-quality jpeg of each image on the external drive, so you can see what the picture is, though not at its full resolution. I think that’s really useful. However, I am a bit concerned that the DB will potentially get huge.
If I had 100,000 images, and each thumbnail was 20KB, I’d assume that I’d need about 2GB of space on my laptop to hold all this info. That sounds fine, but I just wanted to get confirmation of rough figures.